The proposed research will 1) provide national estimates of sexual behavior, behavior change and other risks for AIDS from a probability sample of the U.S., 2) analyze correlates of AIDS knowledge and behavior change in a mass communication model, and 3) determine correlates of non-response to sexually explicit questions. The analyses will be performed on a national probability sample of individuals in the U.S. collected by Project HOPE between June and September, 1988. These data will provide the first ever estimates of sexual behavior and behavior change applicable to the U.S. population as a whole, including moderate risk individuals not typically ascertained in studies of behavior change. The data include a random cross-section of the U.S. population aged 16-50, including oversampling of males, blacks, and Hispanics (N=1939), and a random sample from designated areas in New York, San Francisco, and Miami known for high HIV prevalence (N=301). The research team consists of experienced AIDS researchers, includ- ing experts in AIDS education and risk behavior, survey research, and medical sociology. The proposed principal investigator directed the design and implementation of AIDS surveys in the U.S., U.K., and France. National estimates of change in abstinence, numbers of partners, use of condoms, and sharing of needles, as well as rates of anal, oral, and vaginal intercourse and sex with bisexuals, prostitutes and IVDU`s will be provided, with confidence intervals and weighted to the U.S. population. In addition, the communications model will provide correlates of behavior change including exposure to AIDS messages in the media, usual media exposure, parochial/cosmopolitan media orientation, predisposition to preventive behavior, personal risk, demographics, AIDS knowledge, and emotional arousal. Finally, methodological analyses will determine correlations of AIDs knowledge and demographic background with willingness to answer sexually explicit questions on a self-completed questionnaire.